Most cellular processes are regulated by reversible protein phosphorylation, which is controlled by protein kinases and phosphatases. Caldera Pharmaceuticals and MedChem Partners propose to develop new probes for characterizing transient protein complexes. MAPK pathways play important roles in cellular differentiation and survival. MAPKs are serine/threonine protein kinases that can phoshorylate both cytoplasmic and nuclear targets. MAPKs are associated with aberrant, chronic or hyper-phosphorylation found in cancerous and other diseased tissues. MAPK complexes are difficult to characterize due to the transient nature of kinase-substrate binding interactions. PUBLIC HEALTH RELEVANCE: Caldera Pharmaceuticals and MedChem Partners propose to develop new probes for characterizing transient protein complexes. MAPK complexes are difficult to characterize due to the transient nature of kinase-substrate binding interactions.